Computer Science Department Seminar

11:30AM-12:30PM, Wednesday, April 21, 2010

Prof. Samir Das, Stony Brook University

Title: Accessing WiFi From Moving Vehicles


Broadband wireless network access from moving vehicles is an emerging area of interest. WiFi technology provides a great potential for such access because of its ubiquity and operation in unlicensed spectrum. However, the performance of WiFi-based communication between a moving vehicle and roadside access points (APs) is often unacceptable, because of high handoff costs, frequent handoffs and poor link quality. We will describe how handoff costs and frequency can be optimized using a new technique called scripted handoff. We will then demonstrate how handoffs and link quality can be further improved via use of steerable directional antennas and beam steering techniques. We will also describe how use of mobility prediction and prefetching can further improve download performance. We will show from real testbed experiments that a combination of the above techniques has the potential to reach the same level of performance offered by 3G cellular data networks while operating in unlicensed spectrum.


Dr. Samir Das is currently a Professor in the Computer Science Department in the State University of New York at Stony Brook. He also serves as one of the directors in the NY State Center of Excellence in Wireless & Information Technology (CEWIT) in Stony Brook. Professor Das received his Ph.D. in Computer Science from Georgia Institute of Technology, Atlanta, in 1994. His research interests are in wireless networking and mobile computing, focusing on protocols, systems and performance evaluation. He received the NSF CAREER award in 1998 and the best paper award in ACM MobiSys conference in 2007. He has been a speaker in the Distinguished Visitor program of the IEEE Computer Society during 2001-03. He co-chaired the technical program committee for the ACM MobiHoc Symposium in 2001 and ACM MobiCom Conference in 2004. Prof. Das currently serves or has served on the editorial board of the IEEE/ACM Transactions on Networking, IEEE Transactions on Mobile Computing, ACM/Kluwer Wireless Networks Journal and Ad Hoc Networks journal.

For more information about this colloquium, please contact Habib M. Ammari at